A disk drive, such as a magnetic disk drive, comprises a magnetic disk, spindle motor, magnetic head, and carriage assembly, which are disposed in a case. The spindle motor supports and rotates the magnetic disk. The magnetic head reads data from and writes data to the magnetic disk. The carriage assembly supports the magnetic head for movement relative to the magnetic disk. The carriage assembly comprises a rotatable arm, and a suspension extending from the arm. The magnetic head is supported on the distal end of the suspension. The magnetic head comprises a slider attached to the suspension, and a head section provided on the slider. The head section comprises a recording head for writing and a read head for reading.
Magnetic heads for perpendicular magnetic recording have recently been proposed in order to increase the recording density and capacity of a magnetic disk drive or reduce its size. In one such magnetic head, a recording head comprises a main pole configured to produce a perpendicular magnetic field, a trailing shield, and a coil. The trailing shield is located on the trailing side of the main pole with a write gap therebetween and configured to close a magnetic path that leads to the magnetic disk. The coil serves to pass magnetic flux through the main pole.
A magnetic head based on high-frequency magnetic field assist recording is proposed in which a high-frequency oscillation element is provided between the main pole and an end portion on the medium side of the trailing shield and a current is applied to the high frequency oscillation element through the main pole and trailing shield.
Recording magnetic poles used in the magnetic head comprising the high-frequency oscillation element is configured so that the across-track size of the oscillation element is substantially equal to that of the main pole. This equality in size can be achieved by a process in which the main pole and oscillation element are milled together. If this milling process is performed using a conventional main pole shape, however, a leakage magnetic field from an across-track edge part of a leading end portion of the main pole is so strong that it inevitably erases or degrades adjacent tracks at the track edge of the leading end portion.